Stevie Davies, as far as I know, has never even attempted to take part in The X Factor. She does not work as a plant stylist or a lifestyle coach for pet manicurists and has not spent exhaustively televised hours having plastic surgery, abusing other races or being taught to samba indifferently. This means that, should you find her work in a bookshop at all, it may not be prominently positioned, despite the TV adaptation of her 1997 novel The Web of Belonging. You may even be unfamiliar with her writing - novels such as the tenderly disturbing Kith and Kin or the truly extraordinary The Element of Water. Davies just writes, very precisely, sometimes wonderfully - sometimes fiction, sometimes non-fiction - and always from the heart. She does what a writer does - making beauty for strangers, passing it on. Which isn't really what the marketplace requires.

Her latest novel, The Eyrie, is a quietly penetrating story of three women, each a resident of the eponymous converted mansion, perched high above a mildly fictionalised post-industrial landscape near Swansea and nearer the coast. The tide leaves them and returns, foxes cry in the night, while they live lives of conviction, of invisible passion, in a community of paper-thin walls and dogged privacy, mutual compromise and small dramas. We'll return to the scale of those dramas later.

First we meet Red Dora, veteran of the Spanish civil war, Scottish communist stalwart, unrepentant activist and still a formidable figure now enjoying her place at the top of the food chain in what was a master capitalist's palace. She is joined by Eirlys: middle-aged, gossipy, the resident who'll bake you superfluous cakes and fuss like the empty-headed, plump codependent she seems to be. An unlikely couple, they meet in Dora's book-lined house, they eat Eirlys' baking and they read - two solitaries occupying their time with anachronistic cultural pleasures, surrounded by an increasingly elderly population.

This lends a certain restraint to the opening chapters, a gentleness and lack of haste, but if Davies is building slowly, she is building to last. And of course neither Dora nor Eirlys is what she seems. The red dragon lost her love in Spain and then lost her only child - Rosa - estranged and then suddenly, shockingly dead in prison. Her daughter is buried nearby, but Dora has never visited the grave. She is a woman of thwarted tenderness and muffled pains who rages against Blair, but is trapped in a failing body and an equally infirm democracy. Eirlys was a Welsh-language activist and has done her own time in prison. Her bland exterior conceals intelligence and a belief in humanity which can seem like innocence, but which represents a political and personal commitment that is just as strong as Dora's.

Then Hannah arrives - another woman alone, this time young and in flight from her marriage. Her husband is not abusive, he is simply the wrong man. Hannah has run away from him, abandoning his two children, and has come to rest near the town where she hopes to trace her father - the parent who abandoned her. For Dora, the young woman becomes the sum of all the ghost daughters she has half-glimpsed down the empty years. Hannah slowly grows into her new freedom, while Dora falls in love, first with the ghost and then with the real young woman she can educate, wake to the world of thought and action, to the cultural values of an old tradition.

And around them, the Eyrie carries on its life, perfectly convincing as a block of flats but lending the novel a deal of its metaphorical weight, widening that apparently domestic scale. As the old civilities quite literally die off, the Eyrie is changing. Young residents arrive with antisocial ways, a frail old woman is bundled out of her flat and into a nursing home by her grasping offspring; the world beyond the Eyrie is full of boy racers, boy soldiers, threats. Dora and Hannah, with their hidden griefs, tell each other to tap on the wall if you want me, like prisoners in their cells. Davies shows us a miniature society that could follow the Thatcherite model and deny its own existence, and then she pulls it back from the brink. For Davies, if humans must live together, then it's humanity that will make life bearable. Individual decisions are allowed a positive as well as a negative potential, with activism of every type a necessity for meaningful survival. Acts of kindness, disciplines, instances of mercy keep the dark at bay.

Not that there's any chance of a Hollywood ending here. Dora has to face incapacity and death - so many years away from Spain, from any context that would have made her struggle heroic. Broken hearts and broken families do not mend. Heroism is visible only to the author's or the reader's eye - because this book is about the enormity, the drama of every life, the fragility of any life. Davies is a writer of deep compassion, the kind which leads her to the darker truths. She shows us ignorance, cruelty, bad luck, second chances that betray and pains that last for decades. But she doesn't leave us without hope, not least in the beauty of her language, in descriptions where a heart can hinge open, delicate as a shell, and in a landscape suffused with history, tangible as the sea air, live as a child's day at the beach.

At the heart of the building and the book is Dora's library, history, invincible knowledge. For Davies, few minds are entirely beyond the reach of learning (the possibilities of the internet dart in and out of view): education that evolves, but still serves the same old purpose - liberating, disturbing, strengthening. And within the heart is a lesson for the reader: that a debased culture, a debased life, can always be renewed, exalted; that kiss anyone and you'll find the taste of tears, the taste of the salt of the earth.